Movable dam.



No. 687,858. 8 Paten ted Dec. 3, I90l. J. H. SHEDD & 0. P. SARLE, In.MOVABLE DAM.

{Application filed Mar. 27, 1901.1

(No Model.) 2 Sheets-Sheet K.

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INVENTOR FIG.5.

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:1 filed Mar. 27, 1901 v (No Model.)

2 Sheets Sheet 2.

WITNESSES INN/5% @M I? Q/VL I "7 Q5" 711! frame, so as to form acontinuous support for the edge 11 when the UNITED STATES 'ATENT EEicE.

JOEL HERBERT SHEDD AND OLIVER PERRY SARLE, JR, OF PROVIDENCE, RHODEISLAND.

MOVABLE DAM.

SPECIFICATION formingpart of Letters Patent No. 687,858, dated December3, 1901.

Application filed March 27, 1901. Serial No. 53,133. (No model.)

T0 at whom it may concern.-

Be it known that we, J oEn HERBERT SHEDI) and OLIVER PERRY SARLE, J r.,citizens of the United States, residing in Providence, in the county ofProvidence and State of Rhode Island, have invented a new and usefulMovable Dam, of which the following is a specification.

Our invention relates to improvements in movable dams.

The objects of this invention are, first, to so hang the dam that itshall automatically gradually open and close, and second, to control theheight of the surface of the water above the dam, so that it will not atany time while the dam is open fall below any given point. We accomplishthese results by means of the device illustrated in the accompanyingdrawings, in which Figure 1 shows a side View of the hanger. This Viewalso illustrates a method of attaching a beam to support the dam by aflange, (marked a,) and also an overhanging flange, (markedla) and a lugwhich is let into the dam, (marked a.) The shape of this flange may bevaried to suit the shape of beam to be used.

Fig. 2 is the reverse side of the hanger and shows the boss or knob,(marked d.) This is on the side and serves to lock the hanger to theframe. I

Fig. 3 is an elevation of the hanger, showing the teeth e, boss d, andflanges a and b.

Fig. 4 shows the movable dam m with the hanger in place and also a frameh to carry it. The teeth 6 mesh with other teeth f on the frame. Thestop 9 extends from frame to cess of weight is in the bottom portion. Asthe dam opens this excessincreases. The dam is made in sections and ishung on frames or other supports.

The hanger is a metallic piece of irregular shape, which is attached tothe movable dam. The grooves, projections, and stops keep it in placeand under control. The operation of a movable dam when working on thesehangers depends on the principle of the pressure of water. The center ofpressure of a body of water of a given depth is at one-third the depthof water from the bottom. If the resisting-point ot' the dam is fixed ata height of one-third the depth of water above the bottom, the pressureof the water is such that the dam, leaving the friction of the mechanismand other retarding forces out of consideration, is just balanced andready to turn on this point. If the volume of water increases, the damwill tip forward or open. When it begins to open, the position of theresisting point rises in our device until it meets the center ofpressure of the water at its new height and is held in its new positionso long as the volume of water flowing remains constant. This processmay be repeated at any number of stages until the dam is fully opened,and the reverse process may be repeated from the position of the damfully opened to closed.- When the dam begins to open, the water willpass both under and over it, thus relieving the pond and at the sametime maintaining the level of the water atits normal height until thevolume is too great to pass through the space vacated by the dam. Whenthe volume of water flowing is diminished, the dam will begin to closeas the center of pressure of the water falls and meets the point ofresistance of the dam, thus cutting ofif gradually the amount of waterpassing under and over the dam. Further, under the above conditions thelevel of the water controlled by this device cannot fall belowa heightequal to the level of the top of the dam when it is closed, as thecenter of pressure of the water and the resistance of the board arebalanced at all stages from the dam in position closed to full open,except in case the water is so dam is fully open.

Fig. 5 is the reverse of Fig. 4.-. The boss d is shown in a groovej inthe position it takes when the dam is closed. It follows this groove andis at the other end when the dam is fully open.

In Fig. 6 the movable dam is shown mounted upon the main dam. The framehis anchored to the main dam by means of bolts and anchorplates. Thenormal surface of the water in the pond above the dam is indicated bythe line w. l

' The dam m is made thicker at the bottom than at the top and weighted,so that the exhigh that it holds the dam fully open against the stopprovided for checking its motion.

Further, the design of this hanger is such that when the dam is fullyopen it will hang at or near the middle, thus balancing the forceexerted from the vacuum created by the water flowing under and over thedam.

We are aware that previous to our invention movable dams have been made.

What we claim as our invention, and desire to secure by Letters Patent,is-

1. The movable dam as heavy, or heavier, below the axis as in the upperportion, hung out of center on a frame by means of a hanger and confinedin place by means of teeth, boss and slot.

2. The hanger herein described, fastened to the movable dam and rollingon a plate frame or rack in such manner that the dam hung out of centerand as heavy or heavier below the axis as in the upper portion will bethrown more out of balance as it is caused to open by an increasing headof water and tend the easier to return to its normal position as thehead of Water decreases.

3. The hanger rolling on a plate, frame 01 rack, confined to itsposition by projections on its face and side or sides.

4. The hanger having the straight part It whereby a substantial seat isafforded to keep the dam from starting to rotate too easily, and thecurved face Zwhereby the dam is allowed to rotate and shift its point ofbearing from its resisting-point when closed to a distance aboutone-half the height of the dam when fully open.

5. The hanger provided with a lateral boss in combination with a plateor frame provided with a groove or other opening in which said bossworks.

In testimony whereof we have signed our names to this specification inthe presence of two suhscribingwitnesses.

J. HERBERT SHEDD. O. PERRY SARLE, JR.,

\Vitnesses:

FRED J. LATHAM, FRED E. CHAPIN.

